TiAlN Research Articles

Experimental Investigation on the Frictional Wear Behaviour of TiAlN Coated Brake Pads

The brake pad is one of the imperative portions of the braking system of any automobile; which is mounted on a brake-disc rotor on each wheel; the brake pads were made by different types of materials. In recent research focuses on using Titanium (Ti) alloy-based brake pads for sophisticated cars (lightweight automobiles) and sports cars because of its high fracture toughness at low density. The most commonly preferred grade of Ti alloy is Grade 2 with 99.5% pure, but in the recent research, it was found that the Ti alloy grade 5 has good thermal stability; so, it can withstand a high tribo-thermal zone like the braking system. This study aims to investigate the frictional wear behaviour of the Ti alloy grade 5 and its performance and it is improved furtherly coating with Titanium Aluminium Nitride (TiAlN). The TiAlN is coated over the Ti alloy using Cathodic Arc Deposition (CAD) method; its surface properties such as surface hardness, surface morphology, surface roughness, and coating thickness are characterized. The wear test is conducted to the TiAlN coated Ti discs as per ASTM G99 (American Society for Testing and Materials) in against OHNS balls (Oil Hardened Nickel Steel). The Coefficient of Friction (COF) of the TiAlN coated Ti alloy has been reduced twice the time when compared with the uncoated Ti alloy. The surface morphology of the worn surfaces studied after the wear test to study the causes of the phenomenon. It reveals that the enhanced surface properties and better resistance to micro thermal effects are reasons for the improved wear resistance of the TiAlN coated Ti alloy.

ВЛИЯНИЕ СТЕПЕНИ ЛЕГИРОВАНИЯ АЛЮМИНИЕМ НА МЕХАНИЧЕСКИЕ И ТРИБОТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ПЛЕНОК НИТРИДА ТИТАНААЛЮМИНИЯВЛИЯНИЕ СТЕПЕНИ ЛЕГИРОВАНИЯ АЛЮМИНИЕМ НА МЕХАНИЧЕСКИЕ И ТРИБОТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ПЛЕНОК НИТРИДА ТИТАНААЛЮМИНИЯ

ВЛИЯНИЕ СТЕПЕНИ ЛЕГИРОВАНИЯ АЛЮМИНИЕМ НА МЕХАНИЧЕСКИЕ И ТРИБОТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ПЛЕНОК НИТРИДА ТИТАНААЛЮМИНИЯВЛИЯНИЕ СТЕПЕНИ ЛЕГИРОВАНИЯ АЛЮМИНИЕМ НА МЕХАНИЧЕСКИЕ И ТРИБОТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ ПЛЕНОК НИТРИДА ТИТАНААЛЮМИНИЯ

Zero temperature coefficient of resistance in back-end-of-the-line compatible titanium aluminum nitride films by atomic layer deposition

Thin film resistors with near-zero temperature coefficient of resistance (TCR) are key passive elements in analog integrated circuits (ICs). State-of-the-art near-zero TCR technology is based on sputtered compounds of Si, Cr, B, and C, which require annealing at temperatures higher than 500 °C, making it incompatible with back-end-of-the-line (BEOL) processes. We report here that near-zero TCR resistors can be obtained by atomic layer deposition (ALD) of TiN-AlN nano-laminates at BEOL-compatible deposition temperature. The resistivity and the TCR can be tuned by varying the ratio between AlN (insulating) and TiN (metallic) in the TiXAl1−XN thin film. The TCR changes from positive to negative as the AlN content is increased, allowing for optimization to zero TCR. The ALD method provides ultimate control of the thickness, composition ratio, coverage, and uniformity. Microstructure analysis shows that the film consists of metallic TiN crystallites embedded in the semiconducting TiyAl1−yN amorphous matrix, suggesting that the electrical behavior is similar to that of SiCr-based compounds. These results pave the way toward BEOL-compatible near-zero TCR thin film resistors, which can significantly reduce capacitance and minimize design complexity of passive analog IC components.

Investigating the structure, adhesion and tribological properties of Al and Zr-doped TiN coatings with various substrate bias voltage and working pressure

In this study, TiAlZrN films were coated on the hardened 1.2344 (X 40 CrMoV 5 1) steels using DC power supplied closed field unbalanced magnetron sputtering (CFUBMS) technique. Structural investigations of coatings were carried out using scanning electron microscope and X-ray diffraction. The thickness of coatings was measured from the cross-sectional scanning electron microscope images, and the grain size value and residual stress were calculated by using X-ray diffraction data in the Scherrer formula. Nano indentation method was used to investigate the surface hardness for reducing the substrate effect due to very thin coating thickness (∼2–3 µm). Scratch test was performed for determining the adhesion strength of the coatings. As a tribo-test, a ball-on-disk system was used. From the results, it was understood why TiAlZrN coatings were attractive. The highest hardness was observed as 50.67 GPa, and the highest scratch resistance was reached to 56 N. Also, it was determined that the coating having the highest tribological properties (5.46 × 10−5 mm3/Nm) increased the wear resistance of the substrate six times (3.06 × 10−4 mm3/Nm).

The influence of specific lubricants on the friction and wear properties of titanium aluminum nitride + solid carbon two-layer coating investigation

The influence of three model lubricants (inactive, surface-active and chemically active) on the friction-wear characteristics of steel—steel friction pairs, steel—coating of titanium aluminum nitride and steel—two-layer coating of titanium aluminum nitride + hard carbon coating is studied. The minimum coeffi cient of friction and the minimum diameters of the wear spot were established for the combination of steel-two-layer coating of titanium aluminum nitride + hard carbon coat ing-orientant in compared media.

Effect of the Degree of Aluminum Doping on the Mechanical and Tribological Characteristics of Titanium–Aluminum Nitride Films

The mechanical and tribological characteristics of titanium–aluminum nitride films deposited by the reactive magnetron sputtering of Ti–Al mosaic targets with different aluminum concentrations were studied. The dependences of the elemental composition, microhardness, and friction coefficient on the degree of doping of the films with aluminum and nitrogen concentration in the Ar/N2 gas mixture during film deposition were obtained. It was found that an increase in the aluminum content in the film results in an increase in film hardness and decrease in the friction coefficient. The optimum nitrogen concentration in the film was achieved at maximum hardness and low values of the friction coefficient. A maximum hardness of 23.5 GPa and a minimum friction coefficient of 0.082 were obtained for films of the composition Ti5AlN1.33, which had a Ti/Al ratio of 5 : 1 and a nitrogen deficiency.

A new approach to model isobaric heat capacity and density of some nitride-based nanofluids using Monte Carlo method

A serious gap in the field of nanofluids' modeling is disregarding the effect of molecular structure that must be highlighted. For the first time, the Monte Carlo method was utilized to model isobaric heat capacity and density of nanofluids. A creditable data set was selected contains nitride-based nanofluids (aluminum nitride, titanium nitride, and silicon nitride all dispersed in ethylene glycol). Quasi-simplified molecular-input line-entry system (quasi-SMILES) was applied to represent the structure of nanofluids, successfully. This format made possible incorporating molecular structure besides experimental conditions into the modeling process. The developed models were evaluated precisely; it was found that the statistical qualities were good and their performance was superior to the classical equation. Also, results revealed that some molecular features of nanofluids such as double and triple bond affects isobaric heat capacity and density, while the size of nanoparticles did not impressive affect these properties. It is remarkable to point out that the proposed models introduce a new trend to estimate the thermophysical properties of nanofluids. The utilized approach could be useful for a more reliable and accurate prediction of the other nanofluids' properties.

Formation and preferential orientation of Au-free Al/Ti-based ohmic contacts on different hexagonal nitride-based heterostructures

Wide-bandgap nitride semiconductors are currently in development for high-power electronic applications. Compositional layered heterostructures of such nitrides result in a high polarization field at the interface, enabling a higher electron mobility, a higher power density, and a higher conversion efficiency. Further optimization of such GaN-based high-electron-mobility transistors can be achieved by evolving from a top AlxGa1−xN barrier toward AlN or even InyAl1−yN. An ongoing challenge in using such hexagonal nitride semiconductors is the formation of a low-resistive, Au-free, ohmic contact far below 1Ωmm. In this paper, we investigate the formation of ohmic contacts by Ti–Al–TiN-based metalization as a function of different annealing temperatures (up to 950°C), Ti–Al ratios (from 15 up to 35 at. %) and nitride barrier composition (AlxGa1−xN, GaN, AlN, and InyAl1−yN). Contacts processed on AlxGa1–x/GaN, and AlN/GaN heterostructures result in low contact resistance of, respectively, 0.30 and 0.55Ωmm, whereas the same contact stack on InyAl1−yN results in resistance values of 1.7Ωmm. The observed solid-phase reaction of such Ti–Al–TiN stacks were found to be identical for all investigated barrier compositions (e.g., AlxGa1−xN , GaN, AlN, and InyAl1−yN), including the preferential grain alignment to the epitaxial nitride layer. The best performing ohmic contacts are formed when the bottom Ti-layer is totally consumed and when an epitaxially-aligned metal layer is present, either epitaxial Al (for a contact which is relatively Al-rich and annealed to a temperature below 660°C) or ternary Ti2AlN (for a relatively Ti-rich contact annealed up to 850°C). The observation that the solid-phase reaction is identical on all investigated nitrides suggests that a further decrease of the contact resistance will be largely dependent on an optimization of the nitride barriers themselves.

A machine learning-based model to estimate the density of nanofluids of nitrides in ethylene glycol

The density of nanofluids is an important thermophysical property whose value is required to evaluate various heat-transfer parameters such as the Reynolds number, the Nusselt number, pressure loss, and the Darcy friction factor. The determination of these parameters is central to the design of many heat-transfer applications. Notably, the density of nanofluids has received relatively little research attention compared with other thermophysical properties. The present study thus focuses on the development of a support vector regression model to estimate the densities of aluminum nitride, titanium nitride, and silicon nitride nanoparticles dispersed in ethylene glycol solution. As inputs, the proposed model uses the mass fraction, temperature, nanoparticle size, and the molecular weight of the nanoparticles. The proposed model predicts the nanofluid densities with high accuracy, as determined by a correlation coefficient of 99.87% and an absolute average relative deviation of 0.0701. To further highlight the accuracy of the proposed model, we compare its results with those of the model of Pak and Cho. The Pak and Cho results deviate considerably from the experimental data except at 298 K. Overall, the proposed support vector regression model is much more accurate than the Pak and Cho model. We thus conclude that the machine learning approach is more reliable for obtaining rapid estimates of the density of nanofluids.

Cutting performance of cubic boron nitride-coated tools in dry turning of hardened ductile iron

A novel cubic boron nitride (cBN)-coated silicon nitride(Si3N4) cutting tool was fabricated via the diamond interlayers by electron cyclotron resonance (ECR) microwave plasma chemical vapor deposition (MPCVD) technique. The cutting performance of cBN-coated tools was evaluated by dry turning of hardened ductile iron in comparison with the commercially available titanium aluminum nitride (TiAlN)-coated tools. The effects of cutting parameters on the cutting force and cutting temperature were studied. The results showed that the cutting forces increased with the increase of depth of cut but decreased with the increase of cutting speed, while the cutting temperature increased with the increase of cutting speed. Compared to the TiAlN-coated tools under identical turning conditions, the cBN-coated tools had lower cutting force and cutting temperature, and smaller tool wear. The cBN-coated tools delivered excellent cutting performance and prolonged tool life. Furthermore, the wear patterns and wear mechanisms of cBN-coated tools were investigated. It was found that the dominant wear patterns were crater wear on rake face and flank wear land, and the wear mechanisms were demonstrated to be abrasion wear and diffusion wear. The cutting experiments verified that the cBN-coated tools had attractive potentials in the applications for dry turning of refractory metals and hardened ferrous materials.

Formability enhancement of high strength steel using modification of contact with friction conditions

ABSTRACT High strength steels are most widely used in automobile industries due to their superior mechanical properties and light weight. However, the formability is poor compared to conventional steels due to high hardness and carbon content. Process parameter, such as, contact with friction condition between the forming tools and the blank can be modified to enhance formability of high strength steel. In this work, the forming die is coated with Titanium aluminium nitride (TiAlN) and the effect of TiAlN thin film coating on the formability of EN10 131 high strength steel is investigated. Small circular cup geometry is chosen for deep drawing experiments and Taguchi technique is used to design the experiments with different levels of the process parameters. The novelty of this study lies in the use of surface coating on the forming tool to modify the friction conditions that exist between high strength steel blank and the die. TiAlN coating on the die has improved the formability of steel considered. The analysis of variance is carried out to study the influence of process parameters on the maximum punch force and their contribution was computed. Contact with friction condition plays a major role, in addition to the blank diameter, in improving the sheet metal formability. The quality of the deep drawn part, in terms of thickness distribution, is influenced by TiAlN-coated die surface

Experimental and statistical investigation into micro-EDM of Hastelloy-X using PVD diamond coated and AlTiN coated tungsten carbide electrodes

This paper investigates the effectiveness of electrode coating during the micro-electro-discharge machining (micro-EDM) of a nickel-based Hastelloy X (Ni-X) using uncoated, physical vapour deposition (PVD) diamond-coated, and aluminium titanium nitride (AlTiN)-coated tungsten carbide tool electrodes. The Box-Behnken design (BBD) along with response surface methodology (RSM) was used for modelling the effect of different machining parameters, i.e., capacitance, voltage, tool rotational speed, and tool coating on the micro-EDM performance of Ni-X alloy. The micro-EDM performance was evaluated by machining time, tool wear, crater size and surface microhardness. Capacitance and voltage were found to have significant effect on machining time, tool wear and crater sizes. Increasing capacitance and voltage reduced the machining time as well as tool wear however, crater size was increased indicating rougher machined surface at higher capacitance and voltage settings. [Submitted 19 November 2018; Accepted 18 June 2019]

An approach to predict the isobaric specific heat capacity of nitrides/ethylene glycol-based nanofluids using support vector regression

Abstract This study presents a novel strategy based on Bayesian support vector regression for the estimation of the specific heat capacity of nitrides/ethylene glycol-based nanofluid. The nanoparticles considered are aluminium nitride (AlN), silicon nitride (Si3N4) and titanium nitride (TiN). The proposed model was built using simple and easy-to-obtain inputs such as the size of the nanoparticles (20, 30, 50, and 80 nm), the molar mass of the nanoparticles, mass fraction of nanoparticles (0.01 - 0.1) and the temperature (288.15 K, 298.15 K, and 308.15 K). Our suggested model showed better prediction accuracy over the analytical models for the estimation of specific heat capacity of nitrides/ethylene glycol nanofluids. Given the simplicity of the model inputs and the accuracy of the model, the approach presented provides a more reliable prediction of specific heat capacity of nitrides-ethylene glycol-based nanofluids than previous models.

Effects of refractory nitride reinforcements on the microstructure, densification and microhardness of Ti6Al4V-based binary composites produced by spark plasma sintering

The effects of different refractory nitrides: aluminium nitride (AlN), titanium nitride (TiN) and hexagonal boron nitride (h-BN) reinforcements on the microstructure, densification and microhardness characteristics of spark plasma sintered Ti6Al4V-based binary composites were studied. The microstructure was examined by optical microscopy, densification was evaluated according to the method of Archimedes and the microhardness of the sintered composites was measured by Vickers microhardness tester. The SPS technique was successfully used to consolidate Ti6Al4V powder and 3 wt.% nanoparticles of AlN, TiN and h-BN respectively. The binary composites produced attained nearly full theoretical densification (98.22 to 99.54%) due to enough diffusional mass transport ensuing in solidly bonded compact of the matrix and the refractory nitride reinforcements. Ti6Al4V-3h-BN composite gave the optimal combination of relative densification and microhardness values of 99.54% and 7.03 GPa which exceeds 200% that of the monolithic alloy and about 48% superior to both composites with TiN and AlN reinforcements.

The Outcome of Turning Factors on the Machining Characteristics While Turning 655M13 Steel Alloy using Tialn Coated Carbide Insert

This exploration is carried out to reveal the outcome of turning factors such as cutting velocity, depth of cut and feed rate on the surface roughness, mean cutting force and tool-work interface temperature on turning cylindrical 655M13 steel alloy components. The experiments are designed based on (33) full factorial design and conducted on a turning centre with Titanium Aluminium Nitride (TiAlN) layered carbide tool of 0.8mm nose radius, simultaneously cutting forces such as feed force, thrust force and tangential force and the tool-work interface temperature are observed using calibrated devices. The surface roughness of the turned steel alloy parts is deliberated by means of a precise surface roughness apparatus. Prediction models are created for average surface roughness, mean cutting force and tool-work interface temperature by nonlinear regression examination with the aid of MINITAB numerical software. The optimum machining conditions are confirmed with the aid of a Genetic Algorithm. The outcome of each turning factor on the surface roughness, mean cutting force and tool-work interface temperature is studied and presented accordingly.

Consolidation of Ti6Al4V alloy and refractory nitride nanoparticles by spark plasma sintering method: Microstructure, mechanical, corrosion and oxidation characteristics

Ti6Al4V alloy combines excellent mechanical and chemical characteristics attractive in some important applications in the automotive and aerospace industries but its insufficient hardness and high-temperature oxidation subdue its extensive use. This work was undertaken to modify the microstructure and improve the current limitation of Ti6Al4V alloy with the intention of not affecting its desirable properties. Therefore, the effects of different refractory nitrides: aluminium nitride (AlN), titanium nitride (TiN) and hexagonal boron nitride (h-BN) reinforcements on the microstructure, mechanical, chemical and oxidation properties of spark plasma sintered Ti6Al4V-based binary composites were investigated. Spark plasma sintering technique was effectively utilized to consolidate the Ti6Al4V powder and 3 wt% nanoparticles of AlN, TiN and h-BN respectively. The microstructure and phase composition of the sintered composites were examined by scanning electron microscopy, optical microscopy, and X-ray diffractometry; densification was evaluated according to Archimedes' principle and microhardness was measured by Vickers’ microhardness test. The corrosion and oxidation behaviour of the samples were studied by linear polarization experiment and thermal gravimetric analysis respectively. It was found that the binary composites produced attained almost full theoretical relative densification (98.23–99.54%) due to adequate diffusional mass transport in solidly bonded particles at the matrix-reinforcement interfaces. Ti6Al4V-3h-BN composite gave the optimal combination of relative densification (99.54%) and microhardness (7030 MPa) which exceeds 200% of the monolithic alloy and about 48% superior to both composites with AlN and TiN reinforcements. The yield and ultimate tensile strengths of the matrix were improved by approximately 47% via the AlN and TiN nanoparticle additions and significantly by 116% through the nano-h-BN addition. Ti6Al4V–3AlN demonstrated most superior electrochemical corrosion resistance with a current density of 3.66 μA/cm2 and a polarization resistance of 8760.2 Ω in the sulphuric acid medium while Ti6Al4V–3TiN with the least normalized weight gain of 0.85 mg/cm2 showed the greatest resistance against oxidation in the high-temperature oxidizing environment.

Cutting tools characteristics and coating depositions for hard part turning of AISI 4340 martensitic steel: A review study

With the introduction of novel super cutting hard tool materials the innovative hard part turning process has cogently replaced by conventional grinding operations. Coatings have a deep-seated effect on cutting output characteristics. Coated tools can diminish considerably the coefficient of friction tends to minimisation of machining forces and surface machined roughness of the work even at more cutting paces. Evolution of the cutting practice has been convoyed by the continuous growth of cutting tool performance because of evolution of thin coatings that providing significant characteristics for every cutting setting. The layer on tool acts as imperative pillar in enhancing the wear resistance. Moreover, the cutting tool characteristics can be advanced during exploiting the coating layer Physical Vapour Deposition (PVD) or Chemical Vapour Deposition (CVD) of Titanium nitride (TiN), Titanium Carbonitride (TiCN), Titanium Aluminium Nitride (TiAlN), Aluminium Chromium Nitride (AlCrN) etc. This take stock summarizes the properties of PVD and CVD multilayer coating and further identification of research challenges from the perspective of cutting tool technology related with tribological phenomena. High strength low alloy steels (HSLA), for instance, AISI 4340 steel are extensively used in automotive, defence and aerospace scenario. In view of attaining better process efficiency, this report will map out the tool characteristics that can be practically fill the window for the researchers to accomplish further investigation on the machining performance of this alloy steel.

Investigation of effect of residual stress and interlayer in PVD multilayer TiAlN coating by finite element analysis

Titanium aluminium nitride is a thin hard coating that is industrially applied using the physical vapour deposition (PVD) route. In this work finite element analysis (FEA) has been employed to evaluate the thermal residual stress in PVD multilayer TiAlN resulted during deposition process. These stresses are beneficial as they increase the strength of coating, but higher values of stress can lead to failure in the coating. The radial and shear residual stresses were evaluated at the free radial edges for different thickness of coatings to demonstrate the influence of coating thickness. The influence of interlayer on residual stress was also investigated. The radial and shear stresses were calculated for different thicknesses, thermal expansion ratios and Young's moduli of interlayer. The results indicated that the interlayer has the highest influence on thermal residual stresses.

Vpliv elektromagnetnih polj na mikrostrukturo in lastnosti trdih prevlek na osnovi Cr(Ti)AlN, pripravljenih s platiranjem v ionskem obloku

Vpliv elektromagnetnih polj na mikrostrukturo in lastnosti trdih prevlek na osnovi Cr(Ti)AlN, pripravljenih s platiranjem v ionskem obloku

Effects of gas flow on detailed microstructure inhomogeneities in LPCVD TiAlN nanolamella coatings

Depositing homogeneous TiAlN coatings with a high Al content on cutting tool inserts is a challenging task. In this work, high-Al cubic Ti1-xAlxN coatings (average x = 0.8) with periodic Ti(Al)N (x = 0.5) and Al(Ti)N (x = 0.9) nanolamellae structure were synthesized by low pressure chemical vapour deposition (LPCVD) with different gas flow velocities, and the detailed microstructure was investigated by electron microscopy and simulations. Using a high gas flow rate, the columnar TiAlN grains with regular periodic nanolamella structures disappeared, the coating became enriched in Ti and hexagonal AlN (h-AlN) formed in the coating. The high Ti content is suggested to be caused by the high gas flow rate that increases the mass transport of the reactants. However, this does not influence the Al-deposition much as it is mainly limited by the surface kinetics due to the relatively low deposition temperature. Density functional theory (DFT) modelling and electron microscopy showed that h-AlN tends to form on the Ti(Al)N phase with a specific crystallographic orientation relationship. The Ti enrichment due to high gas flow rate promotes the formation of h-AlN, which therefore deteriorates the nanolamella structure and causes the disappearance of the columnar TiAlN grains. Thus, by designing the CVD process conditions to avoid too high gas flow rates, homogenous TiAlN coatings with high Al content and nanolamella structures can be deposited, which should yield superior cutting performance.